use std::sync::Arc;
use std::time::Duration;

use tracing::{debug, warn};
use uuid::Uuid;

use crate::connect::ConnectClient;
use crate::proto::runner::v1::{LogRow, UpdateLogRequest};
use crate::state::RunnerState;

const POLL_INTERVAL: Duration = Duration::from_secs(3);

/// Log category summary from logs-service.
#[derive(serde::Deserialize)]
struct LogCategorySummary {
    category: String,
    count: i64,
}

/// Streams logs from logs-service to Forgejo while a job is in-flight.
/// Returns the final log index so the reporter knows where we left off.
pub async fn stream_logs(
    client: Arc<ConnectClient>,
    state: Arc<RunnerState>,
    request_id: Uuid,
    task_id: i64,
    logs_base: String,
    mut stop: tokio::sync::watch::Receiver<bool>,
) -> i64 {
    let http = reqwest::Client::new();
    // Track how many lines we've sent per category to only send new ones.
    let mut sent_per_category: std::collections::HashMap<String, usize> = Default::default();
    let mut log_index: i64 = 0;

    loop {
        if *stop.borrow() {
            // Final flush
            log_index = poll_and_send(
                &client,
                &state,
                &http,
                &logs_base,
                request_id,
                task_id,
                log_index,
                &mut sent_per_category,
            )
            .await;
            break;
        }

        log_index = poll_and_send(
            &client,
            &state,
            &http,
            &logs_base,
            request_id,
            task_id,
            log_index,
            &mut sent_per_category,
        )
        .await;

        tokio::select! {
            _ = tokio::time::sleep(POLL_INTERVAL) => {}
            _ = stop.changed() => {
                // Final flush
                log_index = poll_and_send(
                    &client, &state, &http, &logs_base,
                    request_id, task_id, log_index,
                    &mut sent_per_category,
                ).await;
                break;
            }
        }
    }

    debug!(task_id, log_index, "log streamer stopped");
    log_index
}

async fn poll_and_send(
    client: &ConnectClient,
    state: &RunnerState,
    http: &reqwest::Client,
    logs_base: &str,
    request_id: Uuid,
    task_id: i64,
    current_index: i64,
    sent_per_category: &mut std::collections::HashMap<String, usize>,
) -> i64 {
    let categories_url = format!(
        "{}/jobs/{}/logs",
        logs_base.trim_end_matches('/'),
        request_id
    );

    let categories = match http.get(&categories_url).send().await {
        Ok(resp) if resp.status().is_success() => resp
            .json::<Vec<LogCategorySummary>>()
            .await
            .unwrap_or_default(),
        _ => return current_index,
    };

    // Check if there are any new lines at all
    let has_new = categories.iter().any(|c| {
        let prev = sent_per_category.get(&c.category).copied().unwrap_or(0);
        c.count as usize > prev
    });
    if !has_new {
        return current_index;
    }

    let mut log_index = current_index;

    for cat in &categories {
        let prev_sent = sent_per_category.get(&cat.category).copied().unwrap_or(0);
        if (cat.count as usize) <= prev_sent {
            continue; // No new lines in this category
        }

        // Fetch all lines for this category
        let url = format!(
            "{}/jobs/{}/logs/{}",
            logs_base.trim_end_matches('/'),
            request_id,
            cat.category
        );

        let text = match http.get(&url).send().await {
            Ok(resp) if resp.status().is_success() => match resp.text().await {
                Ok(t) => t,
                Err(_) => continue,
            },
            _ => continue,
        };

        let all_lines: Vec<&str> = text.lines().collect();
        if all_lines.len() <= prev_sent {
            continue;
        }

        // Only send lines we haven't sent yet
        let new_lines = &all_lines[prev_sent..];

        let now = prost_types::Timestamp {
            seconds: time::OffsetDateTime::now_utc().unix_timestamp(),
            nanos: 0,
        };

        let rows: Vec<LogRow> = new_lines
            .iter()
            .map(|line| LogRow {
                time: Some(now.clone()),
                content: line.to_string(),
            })
            .collect();

        let count = rows.len() as i64;

        let req = UpdateLogRequest {
            task_id,
            index: log_index,
            rows,
            no_more: false,
        };

        match client
            .update_log(&req, &state.identity.uuid, &state.identity.token)
            .await
        {
            Ok(resp) => {
                debug!(
                    task_id,
                    category = %cat.category,
                    new_lines = count,
                    ack_index = resp.ack_index,
                    "streamed logs"
                );
                log_index = resp.ack_index;
            }
            Err(e) => {
                warn!(error = %e, task_id, category = %cat.category, "failed to stream logs");
                log_index += count;
            }
        }

        sent_per_category.insert(cat.category.clone(), all_lines.len());
    }

    log_index
}